Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia.
Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia.
Cont Lens Anterior Eye. 2019 Feb;42(1):49-54. doi: 10.1016/j.clae.2018.03.001. Epub 2018 Mar 13.
To examine the magnitude and time course of central epithelial, stromal and total corneal thickness changes during sealed miniscleral contact lens wear and the influence of initial central corneal clearance upon these thickness changes.
High-resolution OCT images were captured over an 8 h period of miniscleral contact lens wear (using a rotationally symmetric 16.5 mm diameter lens) in 15 young, healthy participants with normal corneae. Corneal thickness data were derived from OCT images using semi-automated image processing techniques over the central 4 mm.
Changes in stromal and total corneal thickness followed a similar pattern throughout lens wear with oedema first detected 15 min after lens insertion (0.47 ± 0.09% increase in stromal and total corneal thickness, both p < 0.01) which peaked after 90 min of lens wear (1.36 ± 0.24% increase in stromal and 1.18 ± 0.20% increase in total corneal thickness, both p < 0.01) and gradually decreased thereafter. Epithelial thickness increased slightly during the first 30 min of lens wear (0.56 ± 0.30% increase, p > 0.05), then rapidly decreased reaching a minimum thickness 480 min after lens insertion (2.38 ± 0.70% decrease, p < 0.05). The maximum total corneal oedema, maximum stromal oedema, and maximum epithelial thinning were not associated with the initial central corneal clearance or the extent of lens settling over the 8 h period (all p > 0.05). Greater initial central corneal clearance resulted in less oxygen concentration reaching the cornea (∼2% less) based on previously published data, which manifested as ∼0.5% more central corneal oedema.
Scleral lens induced corneal oedema is stromal in nature. On average, central stromal and total corneal thickness increased rapidly following lens insertion and peaked after 90 min, while central epithelial thickness gradually decreased throughout lens wear consistent with natural diurnal variation. A greater initial central corneal clearance resulted in reduced oxygen delivery to the cornea, which had minimal short-term impact upon healthy eyes, however, minimising central corneal clearance may be important in eyes with reduced endothelial cell function to minimise hypoxic stress.
研究密封式巩膜接触镜佩戴过程中中央上皮、基质和全角膜厚度的变化幅度和时间进程，以及初始中央角膜间隙对这些厚度变化的影响。
使用旋转对称的 16.5mm 直径镜片，对 15 名健康年轻参与者的正常角膜进行了 8 小时巩膜接触镜佩戴的高分辨率 OCT 图像采集。使用半自动图像处理技术从 OCT 图像中获取角膜厚度数据，覆盖中央 4mm。
在整个镜片佩戴过程中，基质和总角膜厚度的变化模式相似，在镜片插入后 15 分钟（基质和总角膜厚度分别增加 0.47±0.09%，均 p<0.01）首先检测到水肿，在 90 分钟后达到峰值（基质增加 1.36±0.24%，总角膜增加 1.18±0.20%，均 p<0.01），此后逐渐下降。上皮厚度在镜片佩戴的前 30 分钟内略有增加（增加 0.56±0.30%，p>0.05），然后迅速下降，在插入镜片后 480 分钟达到最小厚度（减少 2.38±0.70%，p<0.05）。最大总角膜水肿、最大基质水肿和最大上皮变薄与初始中央角膜间隙或 8 小时内镜片沉降的程度无关（均 p>0.05）。根据先前发表的数据，更大的初始中央角膜间隙导致到达角膜的氧气浓度降低（约 2%），表现为约 0.5%更多的中央角膜水肿。
巩膜镜引起的角膜水肿是基质性的。平均而言，中央基质和总角膜厚度在镜片插入后迅速增加，在 90 分钟后达到峰值，而中央上皮厚度在整个镜片佩戴过程中逐渐下降，与自然昼夜变化一致。更大的初始中央角膜间隙导致到达角膜的氧气输送减少，这对健康眼睛的短期影响很小，然而，最小化中央角膜间隙可能对内皮细胞功能降低的眼睛很重要，以最小化缺氧应激。
